Tissue or miscarriage?

Alex • Somos tortugas en esta vida

Okay so a little bit of TMI background. I take birth control and am on the pill. My bf typically finishes inside of me. 3 weeks have passed since he last did, but a few days ago I got very drunk and masturbated. I ended up bleeding profusely which has never happened when I masturbate, but it stopped after 2 days. I chalked it down to going too rough but just today I looked in my underwear and saw this. Nothing else like blood or dark discharge has shown up.. only this. After thinking about the getting drunk and the amount of watery blood that happened a week ago on top of the fact that I’ve never seen anything like this.. I’m starting to think I had a miscarriage. Did I? Or is this just leftover blood.. even if it is an insanely tiny and concentrated thing.